public class Solution {
public intlengthOfLongestSubstring(String s){int n = s.length();int ans =0;for(int i =0; i < n; i++)for(int j = i +1; j <= n; j++)if(allUnique(s, i, j)) ans = Math.max(ans, j - i);return ans;}
public boolean allUnique(String s,int start,int end){
Set<Character> set = new HashSet<>();for(int i = start; i < end; i++){
Character ch = s.charAt(i);if(set.contains(ch))return false;
set.add(ch);}return true;}}